const array = [1,2,3,4,5,6,7,8,9]

// 经典for循环
for (let i = 0; i < array.length; i++) {
    console.log(array[i]);
}

// for in循环
for (let index in array) {
    console.log(array[index]);
}

// for of循环
for (let element of array) {
    console.log(element);
}